Eucalyptus essential oil is a refreshing and invigorating oil that is derived from the leaves of the eucalyptus tree. It has a clean, menthol-like aroma that is both stimulating and rejuvenating, making it a popular choice for use in aromatherapy and perfumery. In aromatherapy, eucalyptus essential oil is often used to promote respiratory health and clear the mind. It is also believed to have antibacterial and antiviral properties, making it a useful oil to use during cold and flu season.